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# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
# Copyright (c) 2014, Nicolas P. Rougier. All rights reserved.
# Distributed under the terms of the new BSD License.
# -----------------------------------------------------------------------------
import re
import math
import numpy as np
# ------------------------------------------------------------------ Matrix ---
class Matrix(object):
def __init__(self, a=1, b=0, c=0, d=1, e=0, f=0):
self._matrix = np.array([[a, c, e],
[b, d, f],
[0, 0, 1]], dtype=float)
@property
def matrix(self):
return self._matrix
def __array__(self, *args):
return self._matrix
def __repr__(self):
a, c, e = self._matrix[0]
b, d, f = self._matrix[1]
return "Matrix(%g,%g,%g,%g,%g,%g)" % (a, b, c, d, e, f)
# ---------------------------------------------------------------- Identity ---
class Identity(Matrix):
def __init__(self):
Matrix.__init__(self)
self._matrix[...] = ([[1, 0, 0],
[0, 1, 0],
[0, 0, 1]])
def __repr__(self):
return "Identity()"
# --------------------------------------------------------------- Translate ---
class Translate(Matrix):
"""
Translation is equivalent to the matrix [1 0 0 1 tx ty], where tx and ty
are the distances to translate coordinates in X and Y, respectively.
"""
def __init__(self, x, y=0):
Matrix.__init__(self)
self._x, self._y = x, y
self._matrix[...] = ([[1, 0, x],
[0, 1, y],
[0, 0, 1]])
def __repr__(self):
return "Translate(%g,%g)" % (self._x, self._y)
# ------------------------------------------------------------------- Scale ---
class Scale(Matrix):
"""
Scaling is equivalent to the matrix [sx 0 0 sy 0 0]. One unit in the X and
Y directions in the new coordinate system equals sx and sy units in the
previous coordinate system, respectively.
"""
def __init__(self, x, y=0):
Matrix.__init__(self)
self._x = x
self._y = y or x
self._matrix[...] = ([[x, 0, 0],
[0, y, 0],
[0, 0, 1]])
def __repr__(self):
return "Scale(%g,%g)" % (self._x, self._y)
# ------------------------------------------------------------------- Scale ---
class Rotate(Matrix):
"""
Rotation about the origin is equivalent to the matrix [cos(a) sin(a)
-sin(a) cos(a) 0 0], which has the effect of rotating the coordinate system
axes by angle a.
"""
def __init__(self, angle, x=0, y=0):
Matrix.__init__(self)
self._angle = angle
self._x = x
self._y = y
angle = math.pi * angle / 180.0
rotate = np.array([[math.cos(angle), -math.sin(angle), 0],
[math.sin(angle), math.cos(angle), 0],
[0, 0, 1]], dtype=float)
forward = np.array([[1, 0, x],
[0, 1, y],
[0, 0, 1]], dtype=float)
inverse = np.array([[1, 0, -x],
[0, 1, -y],
[0, 0, 1]], dtype=float)
self._matrix = np.dot(inverse, np.dot(rotate, forward))
def __repr__(self):
return "Rotate(%g,%g,%g)" % (self._angle, self._x, self._y)
# ------------------------------------------------------------------- SkewX ---
class SkewX(Matrix):
"""
A skew transformation along the x-axis is equivalent to the matrix [1 0
tan(a) 1 0 0], which has the effect of skewing X coordinates by angle a.
"""
def __init__(self, angle):
Matrix.__init__(self)
self._angle = angle
angle = math.pi * angle / 180.0
self._matrix[...] = ([[1, math.tan(angle), 0],
[0, 1, 0],
[0, 0, 1]])
def __repr__(self):
return "SkewX(%g)" % (self._angle)
# ------------------------------------------------------------------- SkewY ---
class SkewY(Matrix):
"""
A skew transformation along the y-axis is equivalent to the matrix [1
tan(a) 0 1 0 0], which has the effect of skewing Y coordinates by angle a.
"""
def __init__(self, angle):
Matrix.__init__(self)
self._angle = angle
angle = math.pi * angle / 180.0
self._matrix[...] = ([[1, 0, 0],
[math.tan(angle), 1, 0],
[0, 0, 1]])
def __repr__(self):
return "SkewY(%g)" % (self._angle)
# --------------------------------------------------------------- Transform ---
class Transform(object):
"""
A Transform is defined as a list of transform definitions, which are
applied in the order provided. The individual transform definitions are
separated by whitespace and/or a comma.
"""
def __init__(self, content=""):
self._transforms = []
if not content:
return
converters = {"matrix": Matrix,
"scale": Scale,
"rotate": Rotate,
"translate": Translate,
"skewx": SkewX,
"skewy": SkewY}
keys = "|".join(converters.keys())
pattern = r"(?P<name>%s)\s*\((?P<args>[^)]*)\)" % keys
for match in re.finditer(pattern, content):
name = match.group("name").strip()
args = match.group("args").strip().replace(',', ' ')
args = [float(value) for value in args.split()]
transform = converters[name](*args)
self._transforms.append(transform)
def __add__(self, other):
T = Transform()
T._transforms.extend(self._transforms)
T._transforms.extend(other._transforms)
return T
def __radd__(self, other):
self._transforms.extend(other._transforms)
return self
@property
def matrix(self):
M = np.eye(3)
for transform in self._transforms:
M = np.dot(M, transform)
return M
def __array__(self, *args):
return self._matrix
def __repr__(self):
s = ""
for i in range(len(self._transforms)):
s += repr(self._transforms[i])
if i < len(self._transforms) - 1:
s += ", "
return s
@property
def xml(self):
return self._xml()
def _xml(self, prefix=""):
identity = True
for transform in self._transforms:
if not isinstance(transform, Identity):
identity = False
break
if identity:
return ""
return 'transform="%s" ' % repr(self)
|
